After all the gentle nudges trying to get my cooling fans to stop going ballistic, I'm still in the same predicament...

P2181 (Malfunction in Engine Cooling System) - sometimes sets CEL, sometimes doesnt

^^ Whenever that code shows up, the cooling fans go absolutely bonkers. Outside temp, engine temp don't matter - Key to on position = full speed cooling fans sounding like a jet engine until 400 seconds after pulling key from ignition. So far the following has been addressed:

Thermostat, Water Pump, WP gasket - all performed with Timing Belt job
Coolant temperature sensor - even though the gauge on the dash was correct, replaced that along with its' little rubber o-ring and even a new plastic C-clip to hold it in place (I didn't even drop the clip! go me!)
Ambient Air Temp Sensor - Chalking this one up to damage from the pothole, I found it strung along the top of the front bumper support, and one wire had been cut clean through. Reattached with soldered joints, re-wrapped, and outside temp displays correctly now (no more -22F when it's 30F in the morning)

Only a few things I can think of that could still be wrong here

1) Engine cooling fan switch: 8D0959481B (don't know where this goes, but can probably find in the Bentley manual) - correct my part number if it's wrong, going by results from the Google machine, so not guaranteeing that's the right part!
2) Cooling Fan Relay (part number unknown) Will again have to look this one up in the Bentley, hopefully they've got a part number for me
3) Bad cooling fan/fan clutch
4) ?????

I've checked the fans by hand (obviously long after they stopped spinning on their own), they spin freely, and the clutches are not terribly warm for being in the engine bay of the beast.

Any further thoughts on diagnostics for me? I absolutely hate it that when I'm sitting at a dead stop, all I can hear is these damn fans and my voltage gauge shows juuuuuust under the 12v mark, sometimes as low as 10v.

Oh, clearing DTC's with the Vag-Com causes the fans to stop going nuts... for a while. Sometimes a few minutes, sometimes a few days of back and forth commute, but they KEEP... COMING... BACK! It wouldn't be so bad, but one thing will sometimes fix it for awhile, but I'm not getting consistent results no matter what I do.

Thanks!
O_E